If they have a private key created with Putty or an ssh client tool, and if they share the associated public key with you, then you can place that public key in your ~/.ssh/authorized_keys file. That way they can access the EC2 instance. That is, they can access it if they understand how to use Putty or some other ssh client. (In theory, you could also give them a private key that matches a public key that you have already added to your authorized keys file, but that is not the way things are usually done, and they would still have to understand how to use an SSH client. Assuming they know how to use SSH, then there is no reason they can't do things the right way, that is no reason they can't access the instance without sharing private keys. They point of private keys, of course, is that they are private. We share public keys, and hide private keys.) The third alternative is to write some kind of web based application that gives them access to selected data on your machine, but that is a more complex proposal.

Great job Charlie! Could you please point me to instructions where I can see how to give others access to my Ubuntu instance? Is it as simple as creating a new key pair and sharing it with them? Thank you!

Charlie, you are correct, I somehow mistakenly installed the pre-selected OS image AWI or some such. I tried to log in using the username you﻿ provided and it suggested that I use the ec2-user as the login account.

One other thought: Are you sure you are using Ubuntu Linux? I'm seeing some documentation that points to ec2-user as the correct user for Amazon Linux, while this video is about installing Ubuntu Linux.

I have tried using ec2-user, and it failed when following the techniques outlined in this video. It may be the right name to use in some cases, but when creating an ubuntu instance, and logging in via SSH, as shown in this video, my attempts to thne log in as the user ubuntu succeed while attempting to log in as ec2-user fail.

Perhaps there are certain cases when ec2-user succeeds for you? If so, please let me know.